The present invention is directed to a device for electroplating portions of parts which are combined into conductive band-like workpiece which is cathodically connected and is continually moved past an anodically connected spray nozzle.
A device for electroplating portions of parts, which are interconnected as a band or strip-like workpiece that is connected as a cathode and is moved past a spray nozzle, which is connected as an anode, is disclosed in U.S. Pat. No. 4,029,555 whose disclosure is incorporated by reference thereto. In this known device, an erect endless band is conducted through a self-contained type of tunnel of an electroplating cell. In the tunnel the band is covered by masks in such manner that only those particular areas or portions which are to be provided with a metallic layer remain exposed. A slot-shaped nozzle, which is connected as an anode is positioned to lay opposite this exposed area in such manner that an electrolyte is sprayed perpendicularly against the band or workpiece. The electrolyte, which flows down and is collected below the slot-shaped nozzle, is subsequently re-used. The length of the slot-shaped nozzle extends practically over the entire length of the electroplating cell and due to the slot-shaped design of the nozzle, the electrolyte emerges relatively uniformly over the entire length of the nozzle. However, as experience has shown, when a plurality of electronic components are combined into individual strips, plates or the band-like workpiece, the beginning and end of the band-like workpiece will exhibit a thicker coating because the current density concentrations at the ends of the strips are greater.
A method and a device for the application of metallic coatings on parts has become known in very general terms and is disclosed in German OS No. 20 17 527. In this particular reference, the individual parts which are to be treated are passed under spray nozzles with the assistance of a conveyor belt. In this arrangement, it has been proposed that if needed, a plurality of spray nozzles can be attached next to one another in the direction of movement and/or behind one another, and, if need be, at both sides. If the application of the metallic coatings is to occur by means of a current, such as in electroplating, the conveyor belt is connected as a cathode and the anodes are disposed in a container filled with the electrolyte and preferably are situated close to the spray nozzles. A partial electroplating, which is limited to specific areas, is not suggested nor disclosed by this particular method and cannot be obtained by this particularly known device.
Another device for selectively electroplating of metals is is disclosed in British Patent Specification No. 1,569,994, which claims priority from the German OS No. 25 51 988. In this device, an electrolyte liquid is applied in the form of a free stream to the stationary surface which is to be provided with the coating. Either the nozzle or a part of the nozzle is connected as the anode and the surface to be electroplated is connected as a cathode.
It has also become known from this disclosure to dispose a plurality of nozzles next to one another and to be opposite one another. Such a nozzle arrangement is provided for the selective partial electroplating of a stationary pin combs. Each pin comb is secured and electrically connected with the assistance of a support mount. The nozzles are secured in a pivotabe support mount and are directed against the pins of the comb. Since the pins are stationary relative to the nozzles, the spacing of the nozzles from one another must be equal to the spacing of the pins on the comb. Since in practice one cannot avoid the fact that the electrolyte streams emerging from the nozzles differ from one another a plating of the different thicknesses will occur on different pins. In this arrangement, the nozzle lie opposite one another. Thus, one cannot avoid the mutual obstruction between the streams of the nozzles which are disposed opposite each other.
A device for plating the terminal pins of a printed circuit board is disclosed in U.S. Pat. No. 4,186,062, whose disclosure is incorporated by reference. In this arrangement, the circuit boards are seized by two belts disposed at both surfaces and conducted through an electroplating cell. The two belts tightly cover the areas of the circuit board which are not to be plated. The electroplating occurs in that the electrolyte is supplied to the board via a plurality of holes which are directed in an upward direction and disposed in a row. With the assistance of a curved surface forming a foil, the electrolyte stream is deflected into a specific direction in such manner that a type of Venturi effect will occur at the circuit board to prevent flow of the fluid into undesired locations.